Strange thing, I built an electronic kit and it half worked. After some testing the fault was found - I'd soldered in a regulator back to front. However the other regulator (wired the same way!) had been working fine. One of those moments in electronics of it works so I'm leaving it. I'm just surprised I managed to keep the magic smoke inside both of them.
For those cusrious about the reference to smoke it's how all electronic components work, they contain magic smoke. One of the most common ways to break them is to put too much electricity through them, this causes them to release their magic smoke. Some (rich) people have a resmoker and assuming they can catch all the escaping smoke they can use that machine to put the smoke back into the component and make it work again.